1. Field of the Invention
The invention relates to a method for the hydraulic branching of an open stream having at least one straight main stream of a specific momentum and having one or more branch streams.
The subject of the invention is also such a hydraulically working channel branch for the distribution of liquids, particularly water, in open channels.
The subject of the invention is, finally, the use of the method and of the channel branch in hydraulic engineering, residential water supply and irrigation technology.
2. Description of the Prior Art
Channel separations of open channels are encountered in highly specific uses of hydraulics, namely where water has to be distributed. Such problems arise both in hydraulic engineering and in residential water supply and irrigation technology. Whereas, in irrigation systems, the water has to be delivered to fields, in the sewage sector water often has to be dispensed to a basin on the longitudinal side by way of distribution channels. In all uses, the particular feature of a uniform distribution plays the central role. However, the great disadvantage of conventional channel branches is that a uniform or controllable distribution of the water has hitherto been impossible on account of breakaway phenomena and the influences of bends. Moreover, the complex phenomenon has largely eluded elementary analysis.
The branching problem mainly involves the throughflow distribution, that is to say the ratio of the throughflows in the laterally diverging channel branch and the continuous channel branch. The effect of the branch stream is persistently influenced by the width ratio ba/bo (ba width of branch channel, bo width of upstream channel), the branching angle .beta. and the through-flow ratio q = Qa/Qo (Qa outflow in branch channel, Qo inflow quantity).
The flow ratios of separating streams have a dead-water zone on the inside of the branch channel and a less pronounced breakaway zone on the outside of the downstream channel. Furthermore, a typical stagnation flow with bottom breakaway is established at the branching edge. The separation streamline on the surface runs approximately axially between the two branches toward the branching edge, whereas the latter extends on the bottom well into the downstream channel. This gives rise to a secondary stream which is in harmony with the breakaway zones and which induces a bottom stream in the direction of the branch channel. Superposed on the primary stream is a spiral secondary stream which, on the surface, flows toward the outside and, on the bottom, therefore flows in the direction of the inside. The water-level drop in the direction of the center of the bend is likewise typical.
The object of the invention is to make such a method for the hydraulic branching of an open stream simple, more effective and better controllable, if possible irrespective of the water level, the inflow quantity, the branching angle and the channel widths.